After semilandmarks

In the 2005 proceedings volume that derived from the predecessor of today's symposium, I plotted an alternate biometrical future “after landmarks” that freed the bioscientist from many severe restrictions of that formalism by instead emphasizing semilandmarks (SL's), which incorporate more anatomical realism than what is possible via the classic anthropometric notion of the landmark point. Today it is time for the same iconoclasm regarding the successor method of SL's, which, like the Procrustes/thin-plate-spline workbench for landmarks, has become canonical prematurely. I will review three domains where optimism about the SL methods may be warranted: heterochrony, bilateral symmetry, and forensic detection. But I will take more time expositing two contexts into which I think the extension of the SL tools will NOT be justified without massive investments in deeper biomathematics. One is the articulation of the SL methods to contexts of bioengineering and biotechnology where dominant scalar summaries such as kinetic, chemical, or elastic energy have no tidy relationship to either of the two principal scalars of the Procrustes approach. The other concerns the context of morphogenesis – there, morphometrics offers far too impoverished a domain of meaningful anatomical descriptions to cope with the biological dynamics of valid diachronic explanations. To summarize in an aphorism, for truly biological problems, the Procrustes class of methods has proved a Procrustean bed, which amputates too much of the actual scientific context in the quest for methodological tidiness. To transcend this dilemma will require new biomathematical structures, not just tinkering with matrix algebra.